A digital set top box (STB) has rapidly spread in recent years largely because the digital STB presents a variety of advantages, compared to general analog televisions, such as it maximized channel usage, improved video and sound signal qualities, and provided a more convenient way to transmit supplementary service data.
Digital (satellite) broadcast system is different from analog broadcast system adapted in general analog televisions in terms of the transmission method of broadcast programs.
Specifically speaking, a digital STB receives a broadcast in a compressively encoded packet stream under an MPEG algorithm, and decodes (restores) the broadcast to original signals before being encoded. An analog television, on the other hand, receives program broadcast signals in analog and regenerates them.
Moreover, the STB, similar to a VCR function in the analog television, allows a user to record or schedule to record in advance (i.e. reserve recording) a particular broadcast program on a particular channel the user selected. The recorded broadcast program data are stored in a memory space like a hard disk in compressively encoded form.
Because of this, many attempted to increase memory capacity in order to record or reserve recording more broadcast programs. However, it is also a well-known fact that increased storage capacity of memory like hard disk is accompanied with increased price. Therefore, in view of price competitiveness, it is rather an unrealistic notion to increase memory capacity for use in the STB without limit.
A conventional device and method thereof are now discussed below.
FIG. 1 is a block diagram of a conventional STB/PVR.
As is seen in the drawing, a STB includes a controller 106 for controlling system components, a tuner 101 for turning received signals, a QPSK decoder 102 for decoding received signals using QPSK modulation, a DEMUX 103 for restoring original independent signals or a group of those signals by separating multiplexed composite signals and restoring them to original signals or a signal group, a MPEG decoder 104 for decoding MPEG audio/video data, an A/V encoder 105 for encoding audio/video video in order to output them to another device, and an internal storage device 107 for storing received data.
In case of a STB or a PVR having a built-in storage device illustrated in FIG. 1, the storage device is fixed in a certain position inside of the product. Hence, when a user wants to add a new program after recording and storing TV broadcasts for a certain period of time, one of already recorded programs had to be deleted, and storage extension to avoid this problem was fundamentally impossible.
According to another traditional embodiment, a separate storage device like a VCR could be added. However, broadcast signals, which are real-time data, cannot be recorded when a tape (for the general VCR) or a storage device (for a STB/PVR with a fixed storage device) is being changed.
Particularly, in case of the conventional fixed storage device, because all individuals could handle and manage recordings only through one single storage device built in the STB/PVR, different users could easily damage files in the storage device and it was virtually impossible to utilize the storage device segregately.
Further, the recordings could not be transmitted, duplicated or stored without the help of an external storage device.
To be short, the fixed storage device, once recording is complete, cannot be independently separated for individual handling or management. For separate handling, a separate external recording device is required to transmit, duplicate and store the stored recordings, but if there is no such external recording device, the fixed storage device normally has to be taken into pieces by a specially trained handling expert therefor. What happens if the storage device is exchanged, extended and separated by a general user not by the handling expert is that when the product with a built-in fixed storage device, which is a magnetic storage device being very sensitive to impact, receives any form of shock during the usage or the separation or installation procedure, it is not buffed from the shock and the surface of the storage device is likely to be damaged thereby. As a result, stability of the product and durability of the recordings cannot be secured.
In other words, a fixed storage device built in the STB/PVR can be easily damaged by internal/external defects and impacts.
However, since the recording device cannot be separately shipped and carried, a separate handling management and transport means is required for the STB/PVR having a built-in fixed storage device.
If the fixed storage device is forcedly separated, recordings therein and the storage device itself can be easily damaged.
That is to say, if the fixed storage device is forcedly separated from the STB/PVR, the already stored recordings and the storage device are often damaged.